Longer answer: Theranos never really got their own custom machines working. Until those machines were working, they did use other machines and processes which did work. However, their entire shtick was trying to do a lot of tests on less blood than usual, so... they simply diluted the blood samples to get enough volume for those machines to function in the first place, and correspondingly, the results were absolute garbage. Effectively, they were using working machines incorrectly to cover up for their non-working machines.
I think it goes further than that, the point is that scientifically the tests could never have worked.
Carreyrou originally got tipped off by pathologists saying that this was impossible, then they got sued into oblivion (see thepathologyblawg).
(IANAP but this is my understanding)
Some real tests rely on having a huge blood sample (e.g. 100ml), being filtered (e.g. by centrifuge) and then a test of a known sensitivity applied.
Theranos claimed that their tests were more sensitive so could work with smaller samples. Statistically this doesn't work because with a finger-prick test (e.g. 1ml) the sample is 100x less likely to contain the target cells - cells are integers.
Additionally finger-prick tests contain only capillary blood - they're filtered by the finger blood vessels only allowing tiny cells - some of the Theranos tests claimed they could detect markers that only exist in arterial and venous blood.
My understanding is that the tests that Theranos actually ran on patients' blood was actually based on drawing blood from the veins, not the finger-prick test. While Theranos did want to do the finger-prick tests--and it wouldn't have worked for the reasons you mentioned--that they didn't get them working meant they couldn't get certification for actually running those tests. So they ran the tests they did get certification for (which was using venous blood draws), for the most part, but even then, they were running tests in ways that violated the procedures they were supposed to be using.
(I do realize that keeping track of how precisely Theranos was lying can be frustrating, since they were doing multiple levels of lying here.)
She wasn't being tried on the technology. The technology had failed, the issue is she knew it didn't work and told people it did to get their money. If the technology worked then even if the business failed with huge losses, there was no fraud.
The presumption of innocence in this case, is that she did not mislead Investors.
My understanding is that it worked in the sense that the results were accurate. But the results were gotten by means other than what the investors/customers thought. So the end-user patients really had no claim since they got correct results. But the companies and investors got scammed bigtime.
I haven't been following the trial closely, but I spent a bit of time skimming through some of the case documents a while back. The government's allegations included a bunch of supporting statements from doctors, who claimed that Theranos frequently gave their patients wildly inaccurate results. It sounds like they weren't able to convince the jury of Holmes' guilt on those charges.
(IIRC, Holmes' lawyers also made the argument that it was not legally possible for her to have committed wire fraud against the patients, because any money that Theranos received would have come from their insurance companies.)
Part of the difficulty is that the empirical data that would have proven how well (or poorly) the technology worked was allegedly stored in a proprietary, bespoke database. When Theranos was ordered to turn over the data to the feds for discovery, they delivered an encrypted copy, and then claimed that the encryption key was lost and the original disk arrays were unrecoverable. Both sides of the case then blamed each other for destroying the last remaining copy of the data, which made for some fun reading.
The vast majority of results were not only not accurate, couldn't possibly have been accurate given the methods they were using to conduct the tests. This is well documented. I suggest John Carreyrou's book, _Bad Blood_, which gets into great detail on this.
Once again, just because some dude wrote it down in a book doesn't mean it's a fact. The jury just acquitted her of those charges. Maybe they didn't the read dude's book?
The jury made no judgements as to the efficacy of the tests. In fact, both the prosecution and the defense stipulated that the Theranos project was a failure. The defense even stated that "Failure is not fraud." The question before the jury was whether or not she had defrauded investors.
They decided that she had.
FWIW, every single firm that had medical expertise declined to invest in Theranos. They could see it had extremely minimal chance of success.
This is wrong. I read Bad Blood by John Carreyrou a few years ago and it mentions there were a lot of false results due to mishandling the blood samples (watering them down to run enough tests etc). I recommend the book if you're interested in the case.
> there were a lot of false results due to mishandling the blood samples
This doesn't hold with what was found in the trial. She was found not guilty on those counts. Just because a dude wrote it down in a book doesn't mean it's true. And the legal process found it to be, in fact, not true.
The jury didn't find that the results given to the patients were accurate. They found that Holmes was not personally, criminally culpable for wire fraud in those cases. Wire fraud is a crime that has very specific elements, well beyond the question of how accurate the test results were.